STUDIES OF THE TRANSITION FROM XEROGELS TO GLASSES IN THE SiO_2-PbO-B_2O_3 SYSTEM WITH DMSO BY TG-DTA-MS TECHNIQUE

摘要

Thermal-mass spectroscopy coupling technique(TG-DTA-MS) was used for studying the thermal decomposition behaivious of the transition from xerogels to glasses for the gradient refractive index materials SiO_2-PhO-B_2O_3 adding Dimethyl Sulfoxide (DMSO) system. Compared with the results of TG-DTA-MS for C_2H_5OH system xerogels , the MS curves for DMSO system xerogels show besides CH_3~+(m/z,15), also CH_2O~+(m/z,31); C_2H_5O~+(m/z,45), [(CH_3)_2SO]~+(m/z,78) etc. positive ion mass spectrum peaks. It indicates that the adding of DMSO enables much residual OR groups to still remain in the forming xerogels. It was benifit for the condensation of the uncompletly hydrolysis product and for preventing the cracking of the xerogels. The priliminary study on the mechanism of thermal decomposition for the DMSO system xerogels was also given in this paper.